It is our objective to develop selective inhibitors of oncorna virus reverse transcriptase of the anthracycline class. This group of drugs is far more potent as oncorna virus reverse transcriptase inhibitors than other reported drugs. A variety of new anthracycline drugs will be synthesized and tested for inhibition of oncorna virus reverse transcriptase using viral RNA, rA:dt10 and dA:dT10 templates. Effective inhibitors will be compared for their capacity to inhibit new virion production and invitro focus formation. Drugs which prevent in vitro focus formation at non toxic concentrations will be studied for power to arrest RNA-virsu-induced cancer formation in vivo using an avian model or oncorna-virus induced murine splenomegaly. The feedback from this data will be used to redesign and synthesize new anthracycline drugs of higher potency and selectivity.